1. Field of the Invention
The present invention relates generally to medical devices, and more particularly, relates to guide wires used for infusion of fluids.
2. Description of the Prior Art
The use of guide wires to easily and properly position diagnostic, therapeutic, and infusion catheters has been known for some time. The above cross referenced commonly assigned patent applications, herein incorporated by reference, describe the state of the art in the design, manufacture, and use of guide wires.
One of the purposes for such guide wires is the positioning of infusion catheters. This procedure requires the attending medical personnel to insert the guide wire into the vascular system through a puncture at a convenient location. The guide wire is normally advanced under fluoroscopy until its distal tip is located at the desired infusion site. The infusion catheter is then advanced over the guide wire until the infusion orifice(s) is located at the infusion site. Oftentimes the guide wire is removed to make the entire cross-sectional area of the infusion catheter lumen available for the passage of fluid.
Because of the difficulties with this procedure, attempts have been made to make an infusion catheter which requires no separate guide wire. U.S. Pat. No. 3,757,768 issued to Kline describes one approach to such a catheter. The Kline design uses a spring guide over which is placed a sheath. To improve the handling characteristics, a removable stylet is inserted into the central infusion lumen. The stylet must be removable to provide the desired infusion properties. However, because it is removable, it is not available to transfer axial torque.